Common sense (the pamphlet)
- For the American independence advocacy pamphlet by Thomas Paine, see Common Sense (pamphlet)
- For the American hip-hop artist, see Common
One meaning of the term common sense (or as an adjective, commonsense) on a strict construction of the term, is what people in common would agree; that which they "sense" in common as their common natural understanding. Some use the phrase to refer to beliefs or propositions that in their opinion they consider would in most people's experience be prudent and of sound judgment, without dependence upon esoteric knowledge or study or research, but based upon what is believed to be knowledge held by people "in common". The knowledge and experience most people have, or are believed to have by the person using the term.
Whatever definition is considered apt, identifying particular items of knowledge that are "common sense" is more difficult. Philosophers may choose to avoid using the phrase where precise language is required. Common sense is a perennial topic in epistemology and widely used or referred to by many philosophers. Some related concepts include intuitions, pre-theoretic belief, ordinary language, the frame problem, foundational beliefs, endoxa, and axioms.
Commonsense ideas tend to relate to events within human experience, and thus commensurate with human scale. Thus there is no commonsense intuition of, for example, the behavior of the universe at subatomic distances or speeds approaching that of light.
Philosophy and common sense
There are two general meanings to the term "common sense" in philosophy. One is a sense that is common to the others, and the other meaning is a sense of things that is common to humanity.
The first meaning was proposed by John Locke in his An Essay Concerning Human Understanding,. This interpretation is based on phenomenological experience. Each of the senses gives input, and then these must be integrated into a single impression. This is the common sense, the sense of things in common between disparate impressions. It is therefore allied with "fancy", and it is opposed to "judgment", or the capacity to divide like things into separates. Each of the empiricist philosophers approach the problem of the unification of sense data in one's own way, giving various names to the operation. However, all believe that there is a sense in the human understanding that sees commonality and does the combining. This is the "common sense".
Two philosophers are most famous for advocating the other meaning of "common sense", the view (to state it imprecisely) that common sense beliefs are true and form a foundation for philosophical inquiry: Thomas Reid, G. E. Moore.
The Scottish philosopher Thomas Reid, a contemporary of Hume and the founder of the so-called Scottish School of Common Sense, devotes considerable space in his Inquiry and the Intellectual Powers developing a theory of common sense. While he never gives a definition, per se, he does offer a number of so-called "earmarks" of common sense (which he sometimes calls "principles of common sense"), such as
- principles of common sense are believed universally (with the apparent exceptions of some philosophers and the insane);
- it is appropriate to ridicule the denial of common sense;
- the denial of principles of common sense leads to contradictions.
Of course, each of these is stated and explained by Reid much more carefully than is done here.
The British philosopher G. E. Moore, who did important work in epistemology, ethics, and other fields near the beginning of the twentieth century, is famous for a programmatic essay, "A Defence of Common Sense". This essay had a profound effect on the methodology of much twentieth-century Anglo-American philosophy. In this essay, Moore lists several seemingly very obvious truths, such as "There exists at this time a living human body which is my body.", "My body has existed continuously on or near the earth, at various distances from or in contact with other existing things, including other living human beings.", and many other such platitudes. He argues (as Reid did before him) that these propositions are much more obviously true than the premises of many philosophical claims which entail their falsehood (such as the claim that time does not exist, a claim of A. N. Whitehead's).
Both Reid and Moore, individually, are famous for appealing to common sense to refute skepticism.
Appeal to common sense is characteristic of a general epistemological orientation called epistemological particularism (The appellation comes from Roderick Chisholm.), which orientation is contrasted with epistemological methodism. The particularist gathers a list of propositions that seem obvious and unassailable and then requires consistency with this set of propositions as a condition of adequacy for any abstract philosophical theory. (An entry on the list, however, may be eventually rejected for inconsistency with other, seemingly more secure, entries.) Methodists, on the other hand, begin with a theory of cognition or justification and then apply it to see which of our pre-theoretical beliefs survive. Reid and Moore are paradigmatic particularists, while Descartes and Hume are paradigmatic methodists. Methodist methodology tends toward skepticism, as the rules for acceptable or rational belief tend to be very restrictive (for instance, being incapable of doubt for Descartes, or being constructible entirely from impressions and ideas for Hume). Particularist methodology, on the other hand, tends toward a kind of conservatism, granting perhaps an undue privilege to beliefs we happen to be confident about.
An interesting question is whether the methodologies can be mixed. For instance, it seems impossible to do logic, metaphysics and epistemology without beginning with some assumptions of common sense. However, particularism applied to ethics and politics often seems simply to entrench prejudice and other contingent products of social inculcation. Is there a way to provide a principled distinction between areas of inquiry where reliance on the dictates of common sense is legitimate (because necessary) and areas where it is illegitimate because it is an obstruction to intellectual and practical progress?
The topic of common sense raises interesting and important questions in a field closely related to epistemology and philosophy of language called "meta-philosophy". Various questions might be raised in a meta-philosophical discussion of common sense: What is common sense? Supposing that a precise characterization of it cannot be given, does that mean appeal to common sense is off-limits in philosophy? Why should we care whether a belief is a matter of common sense or not? Under what circumstances, if any, is it permissible to advocate a view that seems to run contrary to common sense? Should considerations of common sense play any decisive role in philosophy? If not common sense, then should any other similar concept such as "intuition" play such a role? In general, are there "philosophical starting points", and if so, how might we characterize them? Supposing that there are no beliefs we are willing to hold come what may, are there some we ought to hold more stubbornly at least?
Common sense is sometimes regarded as an impediment to abstract and even logical thinking. This is especially the case in mathematics and physics, where human intuition often conflicts with provably correct or experimentally verified results. A definition attributed to Albert Einstein states: "Common sense is the collection of prejudices acquired by age eighteen."
Common sense is sometimes appealed to in political debates, particularly when other arguments have been exhausted. Civil rights for African Americans, women's suffrage, and homosexuality—to name just a few—have all been attacked as being contrary to common sense. Similarly, common sense has been invoked in opposition to many scientific and technological advancements. Such misuse of the notion of common sense is fallacious, being a form of the argumentum ad populum (appeal to the masses) fallacy.
Projects to collect common sense
The Cyc project is an attempt to provide a basis of commonsense knowledge for artificial intelligence systems. The Open Mind Common Sense project is similar except, like other on-line collaborative projects like Wikipedia, was built from the contributions of thousands of individuals across the Web.